"You know where is Carlos?"

Question

I would like to know if the question below is grammatically correct or not or if it can be use in informal speech.

"You know where is Carlos?"

I know I can say:

"Do you know where Carlos is?"

All comments and answers will be appreciated.

Answer 1

Normally it is not grammatical, but see the most upvoted answer here.

We normally need, for example

Do you know where Carlos is?

Or, for another example, just

Where is Carlos? (Where's Carlos?)

Linguists and grammars have several different systems for categorizing question types and forms.

One of the main ways we ask questions is to invert the order of the subject and verb in a verb phrase containing am, is, are, or were as a complement verb ("linking verb").

Carlos is home. → Is Carlos home?

Another way we make questions is to use a "dummy" auxiliary (do or did) with one-word verb phrases that are simple present and simple past tenses other than be.

You know (something/someone). → Do you know (something/someone)?

A third way to form a question is to place a question word (also called wh- words) in front of many sentences (including the two types described above).

Where is Carlos?
Why do you exercise?

In Do you know where Carlos is? we do not need to invert the subject Carlos with the verb is, because the use of do makes the sentence a question.

And where is not a question word in the sentence. It doesn't need a question word, because the do + subject + verb pattern establishes it as a question. Where is a pronoun here, standing for some place.

Adapted from Parrott, M. (2000). Grammar for English Language Teachers. Cambridge: Cambridge University Press, 273-5.

Answer 2

No, of your two examples only the second is correct.

The first one is common among foreign speakers, but it is syntactically incorrect.

In English, your average question comprises of a "question word" (e.g. "what", "do", etc.) and a clause (subject + verb + object).

However, if you get rid of the "is" in your first example, it can become a valid question, but with a different purpose. You know where Carlos is? implies that the receiver of the question does know where Carlos is, and the asker is usually expressing surprise or anticipation.